The Intracellular Ion flux mediated by TMEM176A and TMEM176B is involved in the regulation of Dendritic Cell Functions

International audienceThe regulation of immune cells by intracellular ion channels remains poorly explored. Here we investigated the role of two cation channels encoded by Tmem176a and Tmem176b that are highly expressed in myeloid cells in the immune system. To avoid any functional compensation, we generated double knock-out (DKO) mice, allowing simultaneous deletion of these two highly redundant and coregulated genes using the CRISPR-Cas9 system. The absence of Tmem176a/b significantly impacted antigen processing and presentation to CD4+ T cells in vivo and selectively altered cytokine production by dendritic cells (DCs). Using a novel real-time fluorescence-based system to analyze intracellular trafficking we found that both channels co-localized in highly dynamic post-Golgi vesicles preferentially interacting with, but not accumulating in, acidic organelles. Thus, these results highlight the importance of TMEM176A/B-mediated cation flux for the fine regulation of DC biology

The Intracellular Ion flux mediated by TMEM176A and TMEM176B is involved in the regulation of Dendritic Cell Functions

International audienceThe regulation of immune cells by intracellular ion channels remains poorly explored. Here we investigated the role of two cation channels encoded by Tmem176a and Tmem176b that are highly expressed in myeloid cells in the immune system. To avoid any functional compensation, we generated double knock-out (DKO) mice, allowing simultaneous deletion of these two highly redundant and coregulated genes using the CRISPR-Cas9 system. The absence of Tmem176a/b significantly impacted antigen processing and presentation to CD4+ T cells in vivo and selectively altered cytokine production by dendritic cells (DCs). Using a novel real-time fluorescence-based system to analyze intracellular trafficking we found that both channels co-localized in highly dynamic post-Golgi vesicles preferentially interacting with, but not accumulating in, acidic organelles. Thus, these results highlight the importance of TMEM176A/B-mediated cation flux for the fine regulation of DC biology

Phenotypic Analysis of Immunocompetent Cells in Healthy Human Dental Pulp

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Role of the intracellular ion channels TMEM176A and TMEM176B in the immune system

International audienceIon channels represent attractive targets for the development of new therapies but still remain poorly studied in the immune system, in particular intracellular ion channels. In this work, we explored the role of two highly redundant ion channels named TMEM176A and TMEM176B that are intriguingly strongly expressed both in RORγt+ cells (ILC3, Th17) and immature dendritic cells. To investigate the role of these homologs and avoid any compensation effect, we generated a double KO (DKO) mouse using CRISPR-Cas9. Surprisingly, Tmem176a/b appeared dispensable for the function of RORγt+ cells and in the protective function of type 17 immunity during chemically-induced or infectious colitis. In contrast, antigen presentation by dendritic cells to CD4+ T cells through MHC II was selectively impaired in DKO mice. Using a real-time fluorescence-based system to analyze intracellular trafficking we found that both channels co-localized in highly dynamic post-Golgi vesicles preferentially interacting with, but not accumulating in, acidic organelles. These results indicate that TMEM176A/B ion channels play a predominant role in adaptive immunity as new intracellular components of the intracellular MHC II machinery

RORγt+ cells selectively express redundant cation channels linked to the Golgi apparatus

International audienceRetinoid-related orphan receptor gamma t (RORγt) is a master transcription factor central to type 17 immunity involving cells such as T helper 17, group 3 innate lymphoid cells or IL-17-producing γδ T cells. Here we show that the intracellular ion channel TMEM176B and its homologue TMEM176A are strongly expressed in these RORγt + cells. We demonstrate that TMEM176A and B exhibit a similar cation channel activity and mainly colocalise in close proximity to the trans-Golgi network. Strikingly, in the mouse, the loss of Tmem176b is systematically associated with a strong upregulation of Tmem176a. While Tmem176b single-deficiency has no effect on the course of experimental autoimmune encephalomyelitis, T cell or DSS-induced colitis, it significantly reduces imiquimod-induced psoriasis-like skin inflammation. These findings shed light on a potentially novel specific process linked to post-Golgi trafficking for modulating the function of RORγt + cells and indicate that both homologues should be simultaneously targeted to clearly elucidate the role of this intracellular ion flow